In general, air springs that are interposed between a wheel side and a vehicle body side are mounted in a railway vehicle or the like to suppress vibrations (see FIG. 7). Upper and lower stoppers 101 and 102 for limiting a displacement amount in the vertical direction are provided in the air spring. For example, the upper and lower stoppers 101 and 102 are arranged so as to suppress the range of swaying that is produced by rolling of the vehicle body and prevent the vehicle body from contacting equipment in the surrounding area. The height of the air spring can be adjusted by supplying or discharging air to or from the air spring. For example, when wheels of a railway vehicle are worn out, the air spring is also used as an apparatus for adjusting the height of the vehicle body that has decreased to return the vehicle body height to the original level thereof.
However, when adjusting the vehicle body height, if the height of the air spring is merely raised, a space between the upper and lower stoppers 101 and 102 of the air spring widens and the range of swaying that is produced by rolling of the vehicle body increases, and there is thus a risk of the vehicle body contacting equipment in the surrounding area.
With regard to this problem, for example, Patent Literature 1 discloses an air spring that, by making a space between upper and lower stoppers adjustable, is configured to be capable of preventing a widening of the space between the upper and lower stoppers while adjusting the height of the air spring (see FIG. 8).
In the air spring disclosed in Patent Literature 1, an upper stopper member 103 and a lower stopper member 104 are provided on an upper face plate and a lower face plate, respectively. The upper stopper member 103 is configured to be rotatable. Flat faces 105 and 106 and protruding faces 107 and 108 are provided on the two stopper members 103 and 104. In this air spring, irrespective of whether the height of the vehicle is high or low, the space between the upper and lower stopper members 103 and 104 can be set to a predetermined range by rotating the upper stopper member 103 and selecting whether to cause the protruding faces 107 and 108 to face each other or to cause the flat faces 105 and 106 and the protruding faces 107 and 108 to face each other.